Multi-color crt display system



Oct. 18, 1966 J. MAREZ 3,280,254

MULTI-COLOR CRT DISPLAY SYSTEM Filed 001;. 30, 1963 5 Sheets-Sheet 1 l I l l I 8O 1 l 1 w 2 l I l i o i l I I z 60 w l l I I 8 4o 3 g I E 1 O l g 0 01 I l l 1 l I i l 1 l 55 l a: a: m 20 3 l" l o l a: m l l l I l 1 1 WAVE LENGTH- mp INVENTOR JON/V (/VMU MARE? FIG. 3 BY a) kwk Oct. 18, 1966 J. MAREZ MULTI-COLOR CRT DISPLAY SYSTEM 5 Sheets-Sheet 2 Filed Oct. 30, 1963 oovm OOOO

INVENTOR. JOH/V (IV/Ml) MARE Z @J L.%

Oct. 18, 1966 J. MAREZ 3,280,254

MULTI-COLOR CRT DISPLAY SYSTEM Filed Oct. 30, 1965 5 Sheets-Sheet 5 FIG. 5

INVENTOR. JOH/V (NM/l MARE Z ATTORNEYS United States Patent 3,230,254 lviULTi-CGLQR CRT DESPLAY SYSTEM John Marez, 3497 Lockwood Drive, San Diego, Calif. Filed (let. 3 H63, Ser. No. 320,236 3 Claims. (Cl. PIS-7.85)

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a multi-color display system and more particularly, to a multi-color display system utilizing a single gun cathode ray tube and specifically, to a multi-color display system utilizing a monochromatic single gun cathode ray tube.

In the past, attempts have been made to generate colors in CRT displays. Some of the most common com prise utilizing, for instance, three color phosphors on the face of the CRT which respond to the electron beam, spinning discs which are placed in front of the display as in commercial television and displays utilizing mirrors such as that exemplified in Patent No. 2,552,464 to E. J. Siezen.

In the patent to Siezen the conventional television display tube, utilizing magnetic deflection coils, is modified so that images are generated on three different areas of the receiver tube and then combined through the use of two mirrors into a single composite display.

in a present day display system such as that exemplified by the Naval Tactical Data System, simplicity of construction and speed of color generaton are two major factors in any design consideration. It is also important that the resolution be high and that the color display is versatile and not limited to a narrow range of colors.

An object of the present invention is to provide a multi-color display system which is practical and simple to implement.

A further object of the present invention is to provide a multi-color display system utilizing conventional electro-sta-tic deflection CRTs.

An additional object of the invention is to provide a multi-color display system which has high speed characteristics and high resolution.

Another object of the present invention is to provide a multi-color display system utilizing conventional CRTs incorporating mono-chromatic display tubes.

Further objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with a the accompanying drawings wherein:

FIG. 1 represents the front of a CRT divided for a tri-color display;

FIG. 2 represents the front surface of a CRT divided for a six color display;

FIG. 3 is a sketch of the color spectrum which indicates the dichroic mirrors needed for a six color display;

FIG. 4 illustrates the positioning of the dichroic mirrors and filters for the tri-color display.

FIG. 5 is a perspective illustration of the arrangement of front surface mirrors, dichroic mirrors, and filters illustrated schematically in FIG. 4.

The present invention represents a new method and system for generating a multi-color display from a single gun cathode ray tube. A multi-color display is obtained through the use of color filters, front surface mirrors, dichroic mirrors and magnifying lenses appropriately positioned.

Basically, the working concept involves adding optically two or more colored images to obtain a multi-color display. In order to do this the face of a conventional CRT utilizing, for instance, electro-static deflection is divided into equal areas. Colored filters are then placed in front of the appropriate areas to obtain the multi-color symbols.

Taking into account optical displacement, attenuation of light, etc., the color symbols are combined through the use of dichroic and front surface mirrors to form a composite multi-color display which is viewed by a user of the equipment. Through the use of such a system the composite multi-color display may be seen in its original size or optically magnified or demagnified as desired.

The present system is intended for use with NTDS and radar and utilizes conventional electro-static deflection mono-chromatic CRTs. Through the use of an electrostatic deflection system as compared to a magnetic deflection system one is able to accomplish extremely high deflection speeds which are only limited by the speed of the driving systems. In addition, through the use of a mono-chromatic tube the resolution of the system is enhanced. This is due to the fact that the color blobs or phosphors responsive to color deposited on the interior of, for instance, a television tube are relatively large in size and therefore the resolution is limited in comparison.

FIG. 1 illustrates the manner in which the front surface of a CRT is divided to obtain a three color display. In the system of FIG. 1 a central area 10 is left blank, i.e., no symbols are generated in that portion of the CRT face while the area 11 would be one in which red symbols are generated, area 12, one upon which green symbols are generated and area 13 one upon which blue symbols are generated. The colors are only by way of example and it is to be understood that any appropriate color might be used.

One of the features of the present invention is the fact that many colors may be generaated by simply dividing the face of the CRT into srnaller areas and positioning appropriate filters in front of the areas. Such a system is shown in FIG. 2 wherein the CRT front surface is divided for a six color display. In this example a central area 24) is left blank while red symbols are generated in are-a 21, yellow symbols in area 22, blue green symbols in area 23, orange symbols in area 24, green symbols in area .25, and blue symbols in area 26.

In the present system it is advantageous to arrange the dichroic mirrors in such a Way that succeeding dichroic mirrors will transmit preceding reflected colors. FIG. 3 illustrates the color spectrum which would be present and from which the type of dichroic mirrors needed for a siX color display could be chosen. The reflection is plotted along the vertical axis while the wavelength in millimicrons is plotted along the horizontal axis.

FIG. 4 illustrates a three color system broken down and spread out in depth so that one may visualize the manner in which the display is implemented. The central area 10 upon which the final composite tri-color display appears to lie is left blank. The area 11 upon which the red symbols are generated is at 000 as shown in FIG. 1. Positioned in front of the area 11 is a front surface mirror 14 which is used to reflect the light or the symbols generated in area 11. Spaced from area 11 is area 12 upon which green symbols are generated. Positioned in front of the area 12 is a front surface mirror 16 which reflects the generated symbol to a dichroic mirror 17 which is capable of passing the red light rays. Spaced at 240 is area 13 upon which blue symbols are generated. Positioned in front of area 13 is a front surface mirror 18 which reflects the generated blue symbols onto dichroic mirror 19 which passes the red and green light rays. The composite tri-color display of the red, blue and green arrows and letters would be as shown in the figure.

FIG. 5 is a perspective illustration of the arrangement of elements in accordance with the concept of the present invention as schematically represented in FIG. 4. In FIG. 5 the perspective view of the face of a cathode ray tube which is mono-chromatic is shown as having a red filter 11 in the uppermost or 000 position, a green filter 12 at the lower right hand or 120 position, with the blue filter 13 at the lower left hand or 240 position. Directly in front of the red filter is a flat surface mirror 14 which receives the symbols passing through the red filter and reflects such red coded signals to another flat surface mirror 15 which is disposed in a centrally aligned position. The second mirror 15 is disposed at such an angle as to again reflect the red coded symbols along a path of central alignment as indicated generally by the dash lines at 15a. Directly in front of the green filter 12 a front surface mirror 16 is disposed at such an angle as to reflect the green coded symbols to a dichroic mirror 17 which is positioned in the previously mentioned central optical alignment in common with the flat surface mirror 15. The dichroic mirror 17 is arranged to reflect green coded symbols and pass therethrough red coded symbols; therefore, both red and green signals are transmitted along the path of common optical alignment as indicated by the dash line 17a. Further, the arrangement of FIG. 5 representing in perspective the schematic combination shown in FIG. 4, illustrates a flat sur-face mirror 18 aligned directly in front of the blue filter 13 so as to reflect the blue coded symbols to the common optical alignment previously mentioned. A second dichroic mirror 19 is positioned in the path of common optical alignment so as to intercept the blue coded symbols reflected from the flat surf-ace mirror 18; the dichroic mirror 19 has the capability of passing both red and green symbols while reflecting blue symbols. Therefore at or near 19a, which may be the composite point of view for an observer, the red and green together with blue coded symbols are seen in common optical alignment.

In operation, let it be assumed that three symbols are to -be generated for observation, i.e. friendly, enemy and unknown. Also assume that the color code of friendly, enemy and unknown is green, red and blue, respectively. All enemy symbols will be generated in area 11, all friendlies in area 12 and all unknowns in area 13. The observer, looking only at area and through the techniques employed will see all the symbols.

In that the dichroic mirrors 15, 17, and 19 pass light as well as reflect light the three separate areas 11, 12, and 13 will appear superimposed on central area 10. Therefore the red, blue and green could appear to be in any portion of area 10. The same would hold true for a six color display or any other number of colors that might be desired.

It is to be understood that the setting of the front surface mirrors requires a linear and angular adjustment to compensate for differences in optical displacement of the light rays. In addition, the brightness viewed will be less than the light energy emitted by the CRT phosphor. This light loss is attributed to the color filters, dichroic mirrors and, if a magnifying lens is used, the magnification lens itself. It was calculated that the present system will decrease an object brightness of lamberts to 8.4 lamberts in actual use. However, this is well above the visibility threshold and therefore not a limiting factor in the use of the system.

- The present method of generating a multi-color displayv has many applications due to the ea e of implementation and flexibility whereas other methods are limited due to complexity and speed limitations. In the present invention only one cathode-ray tube with a single gun and a choice of phosphor is needed to obtain multi-color symbols.

The present type of presentation allows extremely high speed color coding of symbols with the only limitations being the CRT characteristics, the outside driving circuits for the deflection circuits and video amplifier re sponse. In addition, with less than 50% light loss in the optical mixer, up to six colors can easily be obtained from a mono-chromatic CRT with a P-4 phosphor.

In addition, although this feature is not illustrated, the front surface mirrors and dichroics may be adjusted so that the viewer obtains the illusion of three dimensional i.e. the red, green and blue symbols may be made to seem to lie in other than the same plane.

Further, through the use of a single tube and associated single g-un eliminates the problem of registration errors due to the electron drift which would be associated with, for instance, a three gun tube. This also follows for the deflection amplifiers, X and Y, and the video amplifier.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A multi-color display system comprising:

a mono-chromatic display tube for displaying symbols in separate areas on the face of the tube;

color filters of a plurality of different colors positioned in front of the tube face for color coding symbols displayer on each said separated area of the tubev face in one of said plurality of different colors; reflective mean positioned adjacent each said separate area for reflecting said color coded symbols to spaced positions of common optical alignment; and, optical means disposed along said spaced positions of comtmon optical alignment and arranged to reflect said color coded symbols to a single composite view area, said optical means including a flat surface mirror arranged to reflect the symbols directed to the first spaced position of common optical alignment and dichroic mirror arranged in an order that permits the transmission of proceeding spaced reflections of color coded symlbols along said common optical alignment to said composite view area.

2. A multi-color display system as set forth in claim 1 wherein:

saidseparate areas are disposed substantially radially relative to said single composite view area.

3. A multi-color display system as set forth in claim 1 wherein:

said separate areas are three in number corresponding to three primary colors of red, blue and green.

References Cited by the Examiner UNITED STATES PATENTS 2,267,813 12/1941 Buckner 178--7.88 2,521,010 9/1950 Homrighous 178-5.2 2,642,487 6/1953 Schroeder l787.86 X

DAVID G. REDINBAUGH, Primary Examiner.

R. L. RICHARDSON, Assistant Examiner. 

1. A MULTI-COLOR DISPLAY SYSTEM COMPRISING: A MONO-CHROMATIC DISPLAY TUBE FOR DISPLAYING SYMBOLS IN SEPARATE AREAS ON THE FACE OF THE TUBE; COLOR FILTERS OF A PLURALITY OF DIFFERENT COLORS POSITIONED IN FRONT OF THE TUBE FACE FOR COLOR CODING SYMBOLS DISPLAYER ON EACH SAID SEPARATED AREA OF THE TUBE FACE IN ONE OF SAID PLURALITY OF DIFFERENT COLORS; REFLECTIVE MEANS POSITIONED ADJACENT EACH SAID SEPARATE AREA FOR REFLECTING SAID COLOR CODED SYMBOLS TO SPACED POSITIONS OF COMMON OPTICAL ALIGNMENT; AND, OPTICAL MEANS DISPOSED ALONG SAID SPACED POSITIONS OF COMMON OPTICAL ALIGNMENT AND ARRANGED TO REFLECT SAID COLOR CODED SYMBOLS TO A SINGLE COMPOSITE VIEW AREA, SAID OPTICAL MEANS INCLUDING A FLAT SURFACE MIRROR ARRANGED TO REFLECT THE SYMBOLS DIRECTED TO THE FIRST SPACED POSITION OF COMMON OPTICAL ALIGNMENT AND DICHROIC MIRRORS ARRANGED IN AN ORDER THAT PERMITS THE TRANSMISSION OF PRECEEDING SPACED REFLECTIONS OF COLOR CODED SYMBOLS ALONG SAID COMMON OPTICAL ALIGNMENT TO SAID COMPOSITE VIEW AREA. 